Device for depositing and stacking bags produced from synthetic resin films and having a bottom seam

Abstract

A device is provided with vertical holding elements for depositing and stacking of plastic bags having welded lower or bottom seams. The holding elements are fixed to crossbeams which extend across an advancing plane in the feeding direction of the bag and are hinged onto an outer circumference of a rotatable support. The support is in the form of an impeller wheel and the crossbeams are set on the support so that the holding elements maintain a vertical position as the crossbeams rotate.

I claim: 
     
       1. A device for manufacturing stacks of bags having a bottom weld seal from a tubular film of a thermoplastic synthetic resin by moving the film in an advancing horizontal plane in increments of, respectively, one bag length in a feeding direction, welding the bottom seam transversely to the feeding direction and cutting the film parallel to the bottom seam, thereby separating each bag from the film and depositing each bag to form a stack, said device comprising a welding and cutting means operating in cycles transversely to the feeding direction for welding the bottom seam and for cutting the film to separate each bag from the film and to form a plurality of separate individual bags, a stacking and conveying unit comprising a revolving support arranged to rotate in a vertical plane transversely to the advancing horizontal plane of the film, said support including crossbeams arranged at uniform spaces along a periphery of the support and transversely to the feeding direction, said crossbeams being equipped with vertically upwardly oriented holding elements for receiving the individual bags severed from the film and deposited thereon to hold a stack of bags, said cross-beams being articulated and guided at the periphery of the revolving support so that during rotation of the revolving support, the holding elements each retain a vertical oriented position along a circular route, and said support including drive means operatively associated with the welding and cutting means for effecting a cyclic rotation corresponding to the space between two neighbored crossbeams after a predetermined number of bags are deposited onto the holding elements of a crossbeam to form said stack of bags. 
     
     
       2. A device according to claim 1, wherein the revolving support comprises an impeller-like frame provided with eight crossbeams arranged at uniform spacings over the periphery of the support, said crossbeams exhibiting a corresponding number of eight standstill positions during one revolution of the support, these positions being attainable by stepwise cyclic rotation of the support according to a stacking cycle. 
     
     
       3. A device according to claim 1 or claim 2, wherein the revolving support is arranged for rotation of the crossbeams from a receiving position of the bags in an upward direction to a higher-level position located above the receiving position. 
     
     
       4. A device according to claim 1, wherein the number of crossbeams corresponds to the number of rest positions along the circular route of the periphery of the support, whereby at least along the route in the revolving direction, in succession, the positions correspond to (a) a receiving station of the bags directly downstream of the welding unit;   (b) an intermediate holding station;   (c) a feeding station for wire bows, said feeding station being associated with a feeding unit for wicket bows, and   (d) a removal station for the stacks of bags.   
     
     
       5. A device according to claim 1, wherein the drive means of the revolving support is controllable by a counter, impulse-controlled by the welding and cutting means, for a cyclic rotation after reaching the number of bags predetermined for one stack, in correspondence with the number of welding steps performed, by an angle corresponding to a mutual spacings of the crossbeams. 
     
     
       6. A device according to claim 1, wherein the cross-beams are equipped with depositing combs leading in the feeding direction and oriented slightly obliquely in the downward direction. 
     
     
       7. A device according to claim 6, wherein the cross-beams exhibit a topside slotted recess arranged in axially offset relationship with respect to the depositing combs. 
     
     
       8. A device according to claim 1, wherein upper ends of the holding elements of a crossbeam of the revolving support in a standstill position serving for reception and depositing of bags are in alignment with the advancing plane of the film or lie somewhat below said plane. 
     
     
       9. A device according to claim 1, wherein the welding and cutting means comprises a welding bar located above the advancing plane transversely thereto and being able to execute a reciprocating vertical motion, said welding bar being located with interspace to the crossbeam located in a receiving position for the bags and further comprising a cutting knife capable of performing a reciprocating motion above the advancing plane, a supporting strip below the advancing plane, and a pressure strip capable of performing a reciprocating motion above the advancing plane being arranged in said interspace in direct succession and in parallel to the welding bar. 
     
     
       10. A device according to claim 9, wherein the pressure strip is equipped with spot welding heads. 
     
     
       11. A device according to claim 1, wherein the spacing of the individual crossbeams from one another correspond to at least about half a length of one bag. 
     
     
       12. A device according to claim 1, wherein the holding elements of the crossbeams are in the shape of stacking tubes for the introduction of wire bows. 
     
     
       13. A device according to claim 1, wherein the holding elements of the crossbeams are in the shape of a pin. 
     
     
       14. A device according to claim 1, further comprising means for moving said tubular film within said advancing plane, means for forming hang-up holes along a top portion of each bag having a bottom weld seam and means for depositing the bags successively onto the rotating support so that the holding elements engage with the hang-up holes.